Résonance magnétique nucléaire de 13C et 17O d'éthers aliphatiques. Effets γ entre les atomes d'oxygène et de carbone

The 13C‐ and 17O‐chemical shifts of 31 aliphatic ethers are measured and discussed. The 17O‐chemical shifts of the ethers ROR′ correlate with chemical shifts for the methylene groups of the corresponding alkanes RCH2R′. The constant of proportionality can be related to the orbital expansion term 〈r−3〉2p. The δc for carbon atoms can also be correlated with δc for the corresponding alkanes. The origin of the correlation is discussed taking into account the conformational modifications resulting from introduction of an oxygen atom in an alkyl chain.